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Showing results for tags 'correct distortion'.
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Hello I'm trying to insert a topographic chart into AutoCAD but the problem that I have is that when the map is scanned it distorts a little bit so that its corners do not match the UTM coordinates that I have specified. I have fixed the rotation of the scanned image using Photoshop CS3 to make the longest line of the map have 0° inclination. Nevertheless, there is always some distortion from the scanning of the map. The map I'm using, I'm trying to insert into AutoCAD with fixed UTM coordinates. To do this, I created a point (bottom left of the map) in AutoCAD and at "properties," I changed its (x, y) positions to match my UTM coordinates, and I created another point (top right) with the specific UTM coordinates that it should have. I changed the limits of my drawing and made them to UTM limits by specifying the values. But the problem I have with my image, is that after I insert it and scaled it, it's corners still don't match the points I created. It can only match one point but with the other point, there will still be some distortion; as shown below: If you look at the map above, the point at the top right is not at the same position as the corner of the map. I cannot fix it because of the distortion of the image from the scanning process. I would have to distort the image to fix it's distortion. But I don't know how to do this in AutoCAD. So my question is: Is it possible to fix image distortion in AutoCAD? Does anyone know how to correct it? I measured the error between the points: it's 26.103 meters. The top right point's coordinates should be (681 324 metres East, 1 009 022 m N). Instead the image's point after scaling is displaced by distortion 26.103 m to the right. Can this be done in AutoCAD? Thank you all very much for your time viewing my post. I'm sure this could just be done very quickly and easily. I'm probably just missing something. To fix this problem I would have to resize the image but the problem is that if I try to resize my image in "properties" I can't change the width without the height changing or vice versa. AutoCAD constrains the proportions of my image. I don't know how to force AutoCAD to not constrain the proportions. I have tried resizing the image in photoshop but it won't do it to exactly 9 decimal numbers to make the other corner fit at its exact UTM location. ----------------------------------------------------------------------------------------------------------------------------------------- PS. I just found a possible solution for my problem in another thread; but, I don't know how to apply it. It says: "Problem: You want to insert a raster image into a drawing, perhaps to trace over it with AutoCAD lines, circles, arcs, etc., but the aspect (width to height) ratio of the raster image isn't correct. Unfortunately, although inserting a raster image seems to be almost identical to inserting a block, you can't specify different x and y scale factors. "Solution: Insert the image at the default 1:1 ratio, and then create a block that includes the image as a component of the block. Now insert the block with different x and y scale factors. Bingo! The image stretches appropriately. Does anyone here know how to create a block that includes the image as a component of it?
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